feat: Installable PWA (#1882)

app/components/PageTheme.js

@@ -0,0 +1,35 @@
+// @flow
+import * as React from "react";
+import { useTheme } from "styled-components";
+import useStores from "hooks/useStores";
+
+export default function PageTheme() {
+  const { ui } = useStores();
+  const theme = useTheme();
+
+  React.useEffect(() => {
+    // wider page background beyond the React root
+    if (document.body) {
+      document.body.style.background = theme.background;
+    }
+
+    // theme-color adjusts the title bar color for desktop PWA
+    const themeElement = document.querySelector('meta[name="theme-color"]');
+    if (themeElement) {
+      themeElement.setAttribute("content", theme.background);
+    }
+
+    // status bar color for iOS PWA
+    const statusElement = document.querySelector(
+      'meta[name="apple-mobile-web-app-status-bar-style"]'
+    );
+    if (statusElement) {
+      statusElement.setAttribute(
+        "content",
+        ui.resolvedTheme === "dark" ? "black-translucent" : "default"
+      );
+    }
+  }, [theme, ui.resolvedTheme]);
+
+  return null;
+}